TI-84 Plus Keyboard Basics
The row of keys under the calculator screen on the TI-84 Plus keyboard contains the keys you use when graphing. The next three rows, for the most part, contain editing keys, menu keys, and arrow keys. The arrow keys
control the movement of the cursor. The remaining rows contain, among other things, the keys you typically find on a scientific calculator.
Keys on the calculator are always pressed one at a time; they are never pressed simultaneously. An instruction such as [2nd][ON] indicates that you should first press [2nd] and then press [ON].
Access the TI-84 Plus functions in blue
Above and to the left of most keys is a secondary key function written in blue. To access that function, first press y and then press the key. For example,
is in blue above the
key, so to use
in an expression, press [2nd] and then press that key.
Use the TI-84 Plus [ALPHA] key to write words
Above and to the right of most keys is a letter written in green. To access these letters, first press [ALPHA] and then press the key. For example, because the letter O is in green above the  key, to enter this letter, press [ALPHA] and then press .
You must press [ALPHA] before entering each letter. However, if you want to enter many letters, first press [2nd][ALPHA] to lock the calculator in Alpha mode. Then all you have to do is press the keys for the various letters. When you’re finished, press [ALPHA] to take the calculator out of Alpha mode.
For example, to enter the word TEST into the calculator, press [2nd][ALPHA][SIN][LN] and then press [ALPHA] to tell the calculator that you’re no longer entering letters.
Use the TI-84 Plus [ENTER] key
The [ENTER] key is used to evaluate expressions and to execute commands. After you have, for example, entered an arithmetic expression (such as 5 + 4), press [ENTER] to evaluate that expression. In this context, the [ENTER] key functions as the equal sign.
Use miscellaneous TI-84 Plus keys
is the key you use to enter the variable in the definition of a function, a parametric equation, a polar equation, or a sequence. In Function mode, this key produces the variable X. In Parametric mode it produces the variable T; and in Polar and Sequence modes it produces the variables
and n, respectively.
The arrow keys
control the movement of the cursor. These keys are in a circular pattern in the upper-right corner of the keyboard. As expected,
moves the cursor to the right,
moves it to the left, and so on.